1. Field of the Invention
The present invention relates generally to apparatuses and methods for measuring body temperature, and more particularly, to apparatuses and methods for enhancing accuracy of contactless body temperature measurement.
2. Description of the Related Art
Conventional thermometers come in two types: contact-type and non-contact type. Contact-type thermometers require physical contact with a target object which is to be measured. Therefore, this type of thermometer cannot give precise readings when used for, e,g., infants who seldom stay still, and if used at nighttime, this type of thermometer may disturb sleep.
In contrast, some non-contact type thermometers measure the wavelength of an infrared emission from a target object with a temperature higher than the absolute temperature to determine the temperature of the target object. This type of thermometer allows for a quick and continuous measurement, without contact, in an accurate way, even when the target is on the move, but this type of thermometer may not be as accurate, e.g., depending on measurement distances.
Commercially available digital thermometers measure temperature by receiving infrared rays from one's ear or forehead using an infrared (IR) sensor. Non-contact thermometers sometimes have a telescopic structure that keeps it at a constant distance from the region where temperature is to be measured.
Carrying a body thermometer all the time can be annoying and impractical, although it indeed comes in handy from time to time.
With increased interest in health and for more efficient health-care, technologies are being developed to provide smartphones or other portable electronic devices with diverse checkup features, e.g., for reading blood pressure, blood sugar, or body fat, and there is also an ongoing effort to provide a body thermometer in the electronic devices.
A sensor of non-contact thermometers for measuring body temperature and an object area at which a temperature is to be measured by the sensor should be spaced part from each other at a predetermined distance to give precise results of body temperature measurement.
However, the telescopic design is difficult to apply to the electronic devices due to structural limitations and variations (and resultant measurement errors) in the distance between the sensor for temperature measurement and the object area.
Although proximity sensors may be adopted for the electronic devices, the proximity sensors can only detect objects on the surface where the detection is to be carried out and the proximity sensors require additional parts, such as separate optic modules including an emitter and a receiver to implement the function.